hotspot with no internet

I am revisiting some code I did a year or so ago trying ot see if there is a better less breakable way to do this.

I want to have a hotspot redirect to a local login page even when there is no internet.

Currently I have a static dns entry that a script enables " .. " however if stuff does not come back online properly this entry could stay enabled and cause lots of problems.

Does anyone have any other ideas? How about if it is not even a hospot anymore is there a nat/firewall rule I can make that redirects them to the local page?

Thanks